AB0140 UTILITY OF MONOCYTES, THEIR SUBSET ANALYSIS, CIRCULATING IMMUNE COMPLEXES AND CYTOKINES IN ASSESSMENT OF SLE DISEASE ACTIVITY
Authors: A. Jha, J. Joseph, S. Prabhu, A. Chaudhary, J. Mathew, B. Yadav
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Systemic lupus erythematosus (SLE) is a heterogeneous disease with interaction of innate and adaptive immunity in pathogenesis and clinical activity. Monocyte and its subset role in SLE disease activity is not well defined. Complement levels and dsDNA levels are used for monitoring but are less than perfect and there is a need for newer prognostic markers in SLE management. <h3>Objectives</h3> To assess the prognostic utility of monocyte subsets,circulating immune complex (CIC) against C1q, cytokines like Tumour necrosis factor-alpha (TNF-a), Transforming growth factor-beta (TGF-b), interleukin-6 (IL-6) in lupus. <h3>Methods</h3> We conducted a prospective observational study in patients with SLE and no flare (as per SELENA-SLEDAI score =&gt;4). A single visit interview of patients along with routine laboratory reports was used to select samples. A voluntary written consent was obtained and a blood sample (10 ml) was collected to separate peripheral blood mononuclear cells (PBMC) and Serum. Cell analysis for monocyte subtypes was done using antibodies against cell surface markers using Fluorescence-activated cell sorting (FACS). Monocyte was sorted as classical and non-classical by CD14 and CD16 expression. Serum cytokines levels of IL-6, TNF-α, TGF-β and circulating immune complexes (CIC) were measured using ELISA kits. <h3>Results</h3> Among the 42 patients of SLE, 22 had active disease and 15 were newly diagnosed cases. The median age was 31 years (IQR 22.75 to 39.25) and the disease duration was 22 months (IQR 0-70.5). Musculoskeletal (76.2%), mucocutaneous (69%), renal (52.4%) and neuropsychiatric involvements (26.2%) were the common organ system involvements. Total monocytes were significantly reduced in active disease and Intermediate monocyte subset was numerically increased but not statistically different in active group(p=0.09). Mean fluorescence intensity (MFI) of CD 163 was significantly elevated in active disease(p=0.006).TNF alpha levels was elevated in active disease(p=0.042) but other cytokines didn't correlate with disease status. CIC levels significantly differentiated active from inactive disease (p&lt;0.001). <h3>Conclusion</h3> CIC along with TNF alpha levels might be a novel valuable predictors of disease activity whereas other serum cytokine levels did not correlate with SLEDAI-based activity. Intermediate subset of monocytes was increased numerically. CD 163 MFI was significantly increased in active SLE and should be evaluated in further studies. <h3>References</h3> [1]Ziegler-Heitbrock L, Ancuta P, Crowe S, Dalod M, Grau V, Hart DN,etal. Nomenclature of monocytes and dendritic cells in blood. Blood (2010) <b>116</b>:e74–80.doi:10.1182/blood-2010-02-258558 [2]Marimuthu, R., Francis, H., Dervish, S., Li, S.C., Medbury, H., Williams, H. Characterization of Human Monocyte subsets by Whole Blood Flow Cytometry Analysis. Journal of Visual Experiments. (140), e57941, doi: 10.3791/57941 (2018). [3]Thanadetsuntorn C, Ngamjanyaporn P, Setthaudom C, Hodge K, Saengpiya N, Pisitkun P. The model of circulating immune complexes and interleukin-6 improves the prediction of disease activity in systemic lupus erythematosus. Scientific Reports. 2018;8(1):2620. Published 2018 Feb 8. doi:10.1038/s41598-018-20947-4 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.